Okay that makes sense. Thanks for clearing that up, I appreciate it.

Alright, sorry for the confusion. I did however not have the tangent space button checked in 2.71 either but the smoothing was set to face. In 2.72b I just removed the smoothing completely and kept the tangent space unchecked and it seemed to work. Is this the intended outcome? Because it seems to me the exact same settings in 2.71 behave differently from 2.72b.

So I noticed the export settings has tangent space greyed out in 2.72b if you have face smoothing set to on. I tried switching the face smoothing off and it seems to fix it in Marmoset at least.

The asset is for a commercial project so I can't share it. I'll try to make another example.

Meant to write "When opening the exact same scene in blender 2.72b and exporting the asset with the same settings as in 2.71 I get normal artefacts in Marmoset."